a self-fulfilling prophecy

Yes.

NO.

But some of them will...and when they do, the people who want to rationalize them will use the excuse that the reason they exist is "self-fulfilling prophecy.

Neither explanation you've received is accurate (by my understanding, at least).

A "self-fulfilling prophecy" is a prediction that comes true partly because of the prediction itself.

For example, let's say a psychic tells a young kid "you will forever be afraid of old women!" and in doing so scares the kid silly, giving him a phobia of old women.

It would have been a self-fulfilling prophecy, because part of the reason it became true is because the of the prophecy itself.

In geopolitics an example would be:

The US president says, "Iran is evil, and we need to be careful with them as we may find ourselves at war with them."

In this scenario, it can be called a self-fulfilling prophecy if it contributes to the worsening of relations between the countries and brings them closer to war.